Division of Forestry and Natural Resources, West Virginia University, Morgantown, West Virginia.
Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing, China.
Glob Chang Biol. 2019 Jan;25(1):68-77. doi: 10.1111/gcb.14484. Epub 2018 Nov 6.
Large-scale planted forests (PF) have been given a higher priority in China for improving the environment and mitigating climate change relative to natural forests (NF). However, the ecological consequences of these PF on water resource security have been less considered in the national scale. Moreover, a critically needed comparison on key ecological effects between PF and NF under climate change has rarely been conducted. Here, we compare carbon sequestration and water consumption in PF and NF across China using combination of remote sensing and field inventory. We found that, on average, NF consumed 6.8% (37.5 mm per growing season) less water but sequestered 1.1% (12.5 g C m growing season ) more carbon than PF in the period of 2000-2012. While there was no significant difference in water consumption (p = 0.6) between PF and NF in energy-limited areas (dryness index [DI] < 1), water consumption was significantly (p < 0.001) higher in PF than that in NF in water-limited regions (DI > 1). Moreover, a distinct and larger shift of water yield was identified in PF than in NF from the 1980s to the 2000s, indicating that PF were more sensitive to climate change, leading to a higher water consumption when compared with NF. Our results suggest NF should be properly valued in terms of maximizing the benefits of carbon sequestration and water yield. Future forest plantation projects should be planned with caution, particularly in water-limited regions where they might have less positive effect on carbon sequestration but lead to significant water yield reduction.
大规模人工林（PF）在中国被赋予了比天然林（NF）更高的优先级，以改善环境和缓解气候变化。然而，在国家范围内，这些 PF 对水资源安全的生态后果考虑较少。此外，很少有研究在气候变化下对 PF 和 NF 的关键生态效应进行比较。在这里，我们使用遥感和实地清查相结合的方法，比较了中国 PF 和 NF 的碳固存和耗水情况。我们发现，平均而言，在 2000-2012 年期间，NF 每生长季消耗的水量比 PF 少 6.8%（37.5 毫米），但固碳量比 PF 多 1.1%（12.5 克碳每生长季）。然而，在能量受限地区（干燥指数 [DI] < 1），PF 和 NF 之间的耗水量没有显著差异（p = 0.6），而在水分受限地区（DI > 1），PF 的耗水量明显高于 NF（p < 0.001）。此外，从 20 世纪 80 年代到 21 世纪，PF 的产水量比 NF 有明显且更大的变化，这表明 PF 对气候变化更为敏感，与 NF 相比，耗水量更高。我们的研究结果表明，在最大化碳固存和产水量效益方面，NF 应该得到适当的重视。未来的造林项目应谨慎规划，特别是在水分受限地区，这些项目可能对碳固存的积极影响较小，但会导致产水量显著减少。
